Dual vibrating beam force transducers, similar to those described in U.S. Pat. Nos. 4,372,173 and 4,724,351, have found use in many devices, including accelerometers, pressure transducers and scales. The transducers generally have the form of a double-ended tuning fork, with a pair of beams extending between a pair of common mounting pads. When used in an accelerometer, for example, the acceleration is converted into a tensile or compression force along the axis of the beams, producing a change in the resonant frequency of the vibrating beams. The frequency change is used as a measure of the acceleration.
Dual vibrating beam force transducers are usually made from crystalline quartz, a feature that allows the transducer to be driven piezoelectrically. However, when the transducer is made from a nonpiezoelectric material, such as silicon, the resonator must be driven by some other means. U.K. Patent No. 2,162,314 describes a miniature double-ended tuning fork transducer that is thermally driven. However, the frequency at which such a transducer can be driven is inherently limited by the thermal time constants involved.